Williams, D; Gerba, P; Maxwell, S,;Sinclair, R. Assessment of the Potential for Cross-contamination of Food Products by Reusable Shopping Bags. Food protection trends, 2011, 31(8): 508-513.
( 8/2011 )
The purpose of this study was to assess the potential for cross-contamination of food products by reusable bags used to carry groceries. Reusable bags were collected at random from consumers as they entered grocery stores in California and Arizona. In interviews, it was found that reusable bags are seldom if ever washed and often used for multiple purposes. Large numbers of bacteria were found in almost all bags and coliform bacteria in half. Escherichia coli were identified in 8% of the bags, as well as a wide range of enteric bacteria, including several opportunistic pathogens. When meat juices were added to bags and stored in the trunks of cars for two hours, the number of bacteria increased 10-fold, indicating the potential for bacterial growth in the bags. Hand or machine washing was found to reduce the bacteria in bags by > 99.9%. These results indicate that reusable bags, if not properly washed on a regular basis, can play a role in the cross-contamination of foods. It is recommended that the public be educated about the proper care of reusable bags by means of printed instructions on the bags or through public service announcements.